In Nugen Mastercheck Pro, there is an 'offset to match" function that sets the output level to the LUFS target level.

Most of the time, the target level is below the actual LUFS, so the result is that the level is lowered when "offset to match" is engaged.

Doing this, both peaks and loudness are lowered (-4dB for example).
Doing this, the integrated PLR (Peak to Loudness Ratio) value shouldn't change (at the top of the PLR strip).
But I experienced that MastercheckPro measures a PLR lowered by 4dB too !

As a test, when I lower the signal level I send to the MasterCheck, le PLR doesn't change. That's fine.

But if I use the "Offset to match" button to lower the output level to a lower LUFS target level, the PLR decreases too.